Wire filaments of the for reinforcing rubber or plastic articles are known. These are used in particular to produce steel cords which are employed as inserts in pneumatic tires for motor vehicles to improve their ride, dynamics and stability as well as to extend their useful life.
Prior to wire filaments being combined and further processed into steel cords they are pretreated and preshaped since as drawn filaments, in the absence of suitable preshaping, they have a fatigue strength which is too low and, in addition, tend to wander out of the tires when straight. In preatreatment, care needs to be taken that the wire filaments do not suffer from the treatment. Particularly when being shaped via gearwheels and the like the high-strength wire filaments receive local pressure points which make them unsuitable for cyclic loading, since such local deformities are the starting points for fatigue fracture occuring.
From DE-AS 1 159 818 a method of producing elastic wire ropes is known, according to which for producing elastic wire ropes of low tension and free of twist in production the wires used in configuring the wire rope are twisted into the range of permanent deformation and then return twisted by twice the range of the windings made up to the return limit. The return limit in this sense is a constant maximum number of twists which a given wire is capable of returning after twisting. Twists exceeding this return limit are not returned, but instead are retained as permanent deformations.
From DE 39 14 330 C2 a method of producing a wire bundle or rope is known in which for stranding the wires they are placed and/or twisted about each other and the resulting strands further twisted together in their direction of twist by means of an overtwist means. By further twisting the strand the latter is twisted past its range of elastic deformation into the range of plastic deformation. To reduce the problems associated with the differing residual torsions of strands produced in such a way, the strand receives downstream of the overtwisting device a low constant tensile stress.